Mass spectrometry of cannabinoids.

The mechanism of fragmentation of cannabinoids to fragments m/e 314, 299, 271, 258, 246, 243, and 231 is given. Cannabidiol cannabinoidiol, cannabinol, delta6- and delta1-tetrahydrocannabinol, cannabichromene, cannabicyclol, derivatives with pentyl, propyl, and methyl side chains, their methyl ethers, and cis-trans and ortho-para isomers were analyzed by GLC-mass spectrometry using different energies for fragmentation during GLC elution. The following mechanism was distinguished: loss of a methyl radical, ring closure and rotation, McLafferty rearrangement, retro Diels-Alder, internal protonation, isomerization and internal bond formation, and one-step fragmentation to m/e 231.